Not to criticize BMW's fabulous 333 horsepower 3.2 litre inline six cylinder engine in the M3 Coupe - or Mercedes-Benz' AMG-modified 349 horsepower 3.2 litre V6 in the C32 AMG - but Audi's modified 340 horsepower 4.2 litre V8 in the 2004 S4 has the edge when it comes to that often forgotten but highly satisfying characteristic of engine performance known as torque! The S4's maximum torque is available much earlier in the rev band which means more immediate throttle response at lower speeds and less need for gear changing. The S4's maximum torque of 302 lb-ft @ 3500 rpm compares to the M3's 262 lb-ft @ 4900 rpm and the C32's 332 lb-ft @ 4400 rpm.

S4 afficionados will note that the previous generation S4 (last seen in 2002) offered a turbocharged 2.7 litre V6 with 250 horsepower at 5800 rpm and 258 ft-lb of torque at just 1850 rpm! Still, the new normally-aspirated, all-aluminum 4.2 litre V8 with 5 valves per cylinder, twin overhead cams, variable valve timing, and variable intake manifold offers 90 more horsepower and 44 more foot pounds of torque overall. Performance is pulse-quickening: Audi quotes a 0 to 100 km/h time of just 5.6 seconds, comparable with the M3 and C32 - and surprisingly, the S4's new V8 gets better overall fuel economy than the previous S4's turbocharged V6 - though it's still awful: 16.7 city/10.7 hwy.

The S4’s V8 is similar to the 4.2 litre engine found in other Audi models, but in order to fit it in to the S4's compact engine compartment, Audi engineers had to relocate the drive chains to the rear of the engine, reducing its overall length to just 464 mm, or about 18 inches. The lightweight aluminum engine weighs only 195 kilograms (430 pounds), which also helps with the car's front/rear weight ratio.

The 2004 S4, based on the redesigned A4, is now available as a sedan or station wagon (Avant). It comes with a standard six-speed manual transmission or optional six-speed Tiptronic automatic transmission with manual-shift capability. In automatic mode, the Tiptronic automatically selects from over 200 shift patterns to match the driver's driving style. In manual mode, the Tiptronic can be shifted with steering wheel paddles or a gear lever which is tapped forwards to shift up and back to shift down.

S4's come standard with Audi "quattro" all-wheel drive system which uses the Torsen torque-sensing centre differential to direct power to the wheels with the most traction. The S4 also has a rear differential lock.

A lightweight, fully independent aluminum suspension based on the A4 includes a four-link front suspension and trapezoidal-link rear suspension. The aluminum setup offers low unsprung mass, which improves ride comfort and handling.

Like the previous S4, the 2004 S4 has clean, aerodynamic styling with just a few subtle S4 styling features. The S4's larger 18 inch tires and wheels and wider stance are the most obvious feature - there's also standard Xenon HID headlamps, a wrap-around front bumper with inset fog lamps, modest fender flares, small side sills, dual rear exhausts, a small lip spoiler, and classy alumuminum mirrors. Small S4 badges can be seen on the grille, trunk lid, and in the interior on the steering wheel and tachometer. In all, a classy package.

Interior

The sporty and well-finished interior includes a leather-wrapped, three-spoke sport steering wheel, 12-way power Recaro sport seats, gray birch wood trim, on the centre instrument panel and doors, grey gauges with metal rings, aluminum door handles, and subtle chrome trim around gearshifter and knob. At night, the gauges are backlit in white while the centre controls, power windows, mirrors and headlight controls are backlit in a vivid red.

S4's come with an automatic climate control system with activated charcoal filter and an Audi Symphony II 10-speaker audio system with an in-dash six-disc CD changer. There's also a standard 60/40 split-folding rear seat, alarm, and remote keyless entry. Optional features include a navigation system, hands-free digitial telephone, OnStar, rear side airbags, and a premium 215 watt Bose sound system.

The S4's cabin is fairly roomy cabin for a compact sedan, and ingress/egress is easy enough. There's adequate front and rear legroom and headroom for four adults, but the rear bench is a bit narrow for three adults.

The superb leather-clad Recaro front sports seats have big side bolsters and thigh bolsters which keep the driver and passenger secure when cornering. The driver's seat includes power height, rake and lumbar adjustments and seat heaters. I found it comfortable but a little confining because of the big side bolsters. I liked the wide dead pedal to the left of the clutch pedal.

There's lots of information available to the driver: in addition to the 7000 rpm redlined tachometer, 280 km/h speedometer, fuel and coolant gauges, there is an information display between the two larger gauges with outside temperature, radio station, and trip computer readouts such as average fuel consumption, distance to empty. The date and time are also displayed in the tachometer.

I liked the slide-out coin drawer and slide-out cupholder in the centre console, and a unique 12 volt powerpoint behind the shift lever that flips over out of site when not being used. The centre folding armrest contains two cupholders but there's not much storage space for CDs.

Even rear passengers have seat heaters with six temperature adjustments, as well as a folding centre armrest that includes two pop-out cupholders and a first-aid kit. Behind the centre armrest is a pass-through to the trunk, and the 60/40 folding seatbacks are released from inside the trunk, to prevent the bad guys from accessing the trunk from inside the passenger cabin.

Noteworthy safety features are three rear height-adjustable head restraints and three 3-point seatbelts, front side airbags, curtain airbags, and as mentioned, optional rear side airbags.

The 380 litre fully lined trunk includes a reflective triangle for use in emergencies. And there's a full-size spare tire and alloy wheel underneath the cargo floor!

Driving impressions

The S4's new V8 engine is a flexible and powerful powerplant that emits exciting, gutteral sounds from the twin exhaust pipes. Equipped with the standard 6-speed manual transmission, Audi quotes a 0 to 100 km/h of 5.6 seconds, but in independent tests conducted by AJAC, a similar S4 averaged just 5.0 seconds over three test runs. What's impressive about this flexible engine is that even in 6th gear at 50 km/h, there's enough torque to pull away cleanly.

The S4's 6 speed manual transmission in my test car offered easy, direct gear changes, clutch engagment was quick, and clutch pedal effort was light. However, under hard shifts I heard a 'thunk' in the all-wheel-drive driveline which suggested some "looseness".

At freeway speeds, the 4.2 litre V8 is quiet and relaxed doing about 2,500 rpm at 100 km/h and 3,000 rpm at 120 km/h. Fuel consumption is thirsty with the manual transmission: 16.7 l/100 km city and 10.7 l/100 km highway. But with the Tiptronic transmission, fuel consumption is considerably better: 14.7 city/9.6 highway.

I found the S4's thick-rimmed, leather-wrapped steering wheel easy to grip, and the rack and pinion variable power assist steering is quick but not too sensitive to input, and light at slow speeds. Its turning circle of 11 metres (36 feet) is tight. The S4 tracks well at highway speeds.

The S4's sublime, neutral handling offers high limits and minimal lean. I found handling exceptional in the wet even with its standard summer performance tires. Despite its sporty suspension and low profile tires, the S4 has a comfortable ride on typical major and secondary paved roads.

All in all, the S4 is a classy act - except for that loose thunk in the driveline.

The primary competitors for the Audi S4 ($67,950) are the Mercedes-Benz C32 AMG ($67,850), and the BMW M3 Coupe ($73,950).

Though they're all high performance German cars, the S4 has all-wheel-drive while the C32 and M3 are rear-drive performance cars. As well, the M3 is a two-door, not a four-door. And though comparable in horsepower, each has a different kind of engine: the S4 has a V8, the C32 a supercharged V6, and the M3 an inline six. All three offer exceptional acceleration and handling performance with 0 to 100 km/h times in the low 5 second range.

Verdict

One of the most impressive compact performance sedans on the market, the Audi S4 is powerful, quick, comfortable, well-equipped and handsome. A high price and a somewhat disturbing looseness in the drivetrain are my only criticisms.